The present invention is generally directed to a control for a motor vehicle and, more specifically, to an automatic climate control.
Typically, automotive climate control heads have utilized an infrared sensor in combination with a thermistor or have utilized an aspirated thermistor by itself. FIG. 1A depicts a typical prior art automotive climate control head 100 with an integrated infrared sensor 102. Such control heads have typically included a number of switch pads 104 for controlling various functions of an automotive climate control system. Such systems have generally also included a display 115 for displaying cabin temperature associated with a driver of the vehicle, as well as, in many cases, an occupant of the vehicle. FIG. 1B depicts a portion of a typical printed circuit board (PCB) assembly 110 that has, in conjunction with the control head 100, allowed an occupant of the vehicle to provide input to the automotive climate control system. As is shown in FIG. 1B, the PCB assembly 110 includes a printed circuit board (PCB) 114 that includes a number of switch contacts that interface with collapsible switch domes 106 of a flexible switch pad 112. As is also shown in FIG. 1B, the display 115 and a sensor holder 116, which positions the infrared sensor 102 an appropriate distance from the PCB 114, are mounted to the PCB 114. With reference to FIG. 1C, the sensor holder 116 has been a molded plastic holder that receives a thermistor 120 and the IR sensor 102 and properly orients the thermistor 120 with respect to the infrared sensor 102. In such a prior art assembly, thermal grease has typically been required to transfer heat from a bottom of the infrared sensor 102 to the thermistor 120.
FIG. 2A depicts a front view of a typical prior art automotive control head 200 that includes an integrated aspirated sensor grill 202 and a plurality of switch pads 204, which provides various input to a climate control system of a motor vehicle. As is also shown in FIG. 2A, the automotive control head 200 includes a display 206, which may display the cabin temperature associated with a driver of the motor vehicle and may also display the cabin temperature associated with a passenger of the motor vehicle. FIG. 2B depicts a cross-sectional view of an aspirated sensor assembly 210, which is located behind the automotive climate control head 200. As is shown in FIG. 2B, the grill 202 is incorporated within a top surface of faceplate 222, which is typically formed in a cylindrical manner and extends from a printed circuit board (PCB) 214 toward an interior of the control head 200. The PCB 214 includes an aperture 224 across which a thermistor 220 is located. A case 226, which houses a fan 228, also includes a grill 230 incorporated at a bottom surface. The fan 228, when in operation, pulls air through the grill 202 and exhausts air out the grill 230. In this manner, cabin air is brought across the thermistor 220 to provide an indication of the current cabin temperature. In an effort to prevent temperature contamination of the thermistor 220 from other components located on the PCB 214, a circular seal 232 has been located between the faceplate 222 and the PCB 214 and a seal 234 has been located between the bottom of the PCB 214 and the case 226. It should be appreciated that sensor assemblies, such as the aspirated sensor assembly 210, as is illustrated in FIG. 2B, includes a number of components which must be individually manufactured and which also require assembly.
What is needed is a temperature sensor holder that can properly transfer heat between an infrared sensor and its associated thermistor that does not require thermal grease. Further, it would be desirable to provide an aspirated sensor for an automotive climate control head that does not require separate seals to block thermal contamination of an associated thermistor.
The present invention is directed to an automatic climate control for a motor vehicle that includes a printed circuit board (PCB), a flexible conductive switch pad and a temperature sensor. The flexible conductive switch pad includes a structure that is formed in conjunction with the flexible conductive switch pad. A switch dome of the flexible conductive switch pad is shaped to make electrical contact with switch contacts formed on the PCB responsive to activation of the switch dome. A portion of the structure includes a localized thermally conductive filler material that uses the conductive switch pad base material for an elastomeric binder and a temperature sensor is positioned within the structure and electrically coupled to sensor contacts on the PCB.
According to another embodiment of the present invention, the structure functions as a ductwork and the thermally conductive material provides temperature isolation for the temperature sensor positioned within the ductwork. According to yet another embodiment of the present invention, the temperature sensor includes an infrared sensor and a thermistor both electrically coupled to different ones of the sensor contacts of the PCB and the structure functions as a temperature sensor holder, which is affixed to the PCB. The temperature sensor holder includes a first recess for receiving the thermistor and a second recess for receiving the infrared sensor and a shape of the temperature sensor holder defines an orientation between the PCB and the temperature sensor. In this embodiment, a portion of the temperature sensor holder that is in contact with infrared sensor and the thermistor is constructed with the thermally conductive filler material within the elastomeric binder of the switchpad, such as silicone rubber, which facilities heat transfer from a base of the infrared sensor to the thermistor.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.